The availability of communication systems is a practical necessity for many aspects of modem society. Data is communicated during operation of a communication system, and such communication of the data effectuates data communication services. Some communication systems are constructed in manners that permit the communication of data, and corresponding effectuation of communication services, over significant distances. Attempts are generally made to maximize the rate at which the data is communicated in the communication system and also to maximize the accuracy of the data that is communicated. As rate of data communication and accuracy of its communication sometimes conflict, a balance is sometimes attempted to be achieved during operation of a communication system.
A communication system is formed of, at a minimum, a set of communication stations that are interconnected by way of a communication channel. At least one of the communication stations of the set forms a sending station. And, another of the communication stations of the set forms a receiving station. And, a communication service is effectuated through the communication of data from a sending station to a receiving station. Communication stations of various communication systems provide for two-way communications in which the communication stations include both transmit and receive portions, capable of transmitting and receiving, respectively, data.
As advancements in technologies permit, improvements to existing communication systems are implemented, and new types of communication systems are developed and deployed. Various of the technological advancements, when implemented, have permitted the effectuation of new types of communication services.
A radio communication system is an exemplary type of communication system. In a radio communication system, data is communicated upon radio channels that are formed between the sending and receiving stations of a communication system. Because radio channels are used upon which to communicate the data, a wireline connection, conventionally required in a conventional wireline communication system to interconnect the sending and receiving stations, is obviated. Communications are thereby effectuable in a radio communication system even when wireline connections cannot be formed.
Radio, as well as other, communication systems, are regularly utilized to communicate data that is subsequently processed by data processing techniques. Advancements in technologies also are applied to the processing of the data. And, communication devices, and communication systems in which the communication devices are utilized, are available by which to perform various data processing operations and communication services. Additional applications and services that implement new data processing and communication technologies shall likely increasingly become available as advancements in technologies permit.
Exemplary devices that are capable of performing both data processing and communication services include devices referred to as personal digital assistants (PDAs). Personal digital assistants are generally of small dimensions of sizes permitting their hand-carriage by a user. Personal digital assistants provide for the storage and processing of data. Databases are stored at the personal digital assistants and the data stored at the databases is selectably retrievable for viewing by the user of the device. And, processing of the data in selected manners is also sometimes permitted. Typically, the data is formatted into a series of data records in which each data record contains one or more data fields. When the device is operated by the user, the user is able selectably to retrieve the data records, or portions thereof. Processing operations performable at the device upon the data, or data fields thereof, include, for instance, sorting operations. And, the user typically is permitted to change, add to, or otherwise alter the data stored at the databases of the device.
The data stored at the device is sometimes also backed-up at another storage device. In the event of loss of the data at the device, a copy of the data is retrievable from the location at which the data is backed-up. Some conventional personal digital assistants have their databases backed-up at a personal computer or other computing station. The backup procedure is usually carried out by interconnecting the device and the computing station together by way of a fixed cable to permit the data to be backed-up. The data stored at either the device or the backed-up location is updatable, i.e., changeable, in an asynchronous manner.
However, by permitting asynchronous changes to the database copies, that is, the database and its backed-up copy, the databases no longer remain true copies of one another. Any addition, deletion, or other change of any data portion causes the data stored at one of the database copies no longer to be in complete conformity with the other of the database copies.
Synchronization operations are performed to place the database copies back into complete conformity with one another. When synchronization operations are performed, the data stored at the respective copies are compared, e.g., on a data record-by-data record or data field-by-data field basis. If the corresponding data at the separate database copies are determined to be out-of-match with one another, the data is caused to be placed back into complete match with one another. When the database copies are connected by way of a radio air interface rather than by way of a wireline connection, data synchronization operations become more problematical than when the same operations are performed when the databases are interconnected by way of a wireline connection. Bandwidth constraints are typically more restrictive in radio communication systems due to limited bandwidth allocations of bandwidth capacities in such systems.
Due to limited bandwidth availability in a radio communication system, a device at which a database copy is maintained might be unable to be used pursuant to other applications when a synchronization operation is being performed to synchronize the database copy with a remotely-stored database copy. And, when the databases are large, the synchronization procedure is lengthy, particularly when the bandwidth available on the radio air interface to perform the synchronization operations is limited.
If a manner could be provided by which a user of the device could control when the synchronization operations are performed, improved use of the device would be possible.
It is in light of this background information related to the synchronization of data of databases by way of a radio air interface that the significant improvements of the present invention have evolved.